Recorded presentation12.3
Relationships between global precipitation and surface temperature on inter-annual and longer time scales during 1979-2006
Robert Adler, NASA/GSFC, Greenbelt, MD; and G. Gu and G. J. Huffman
Associations between rainfall and surface temperature anomalies on the longer-than-seasonal time scales are explored for the period of 1979-2006, using the GPCP precipitation product and the GISS surface temperature data set. Positive (negative) correlations are generally observed between these two variables over tropical oceans (lands) on an inter-annual basis. ENSO is the dominant factor in these inter-annual, tropical relations. In the northern hemisphere mid-to-high latitudes, the correlation relationships between rainfall and temperature anomalies are more complicated with positive and negative values of correlation tending to appear over both oceans and land. Furthermore, there seems a strong seasonal variation in correlation in the north hemisphere middle and high latitudes. Most intense long-term, linear changes in annual-mean rainfall anomalies over the period tend to be within the tropics, as do their largest variances. For surface temperature, however, both the strongest linear changes and largest variances are observed in the north hemisphere mid-high latitudes, with much weaker temperature changes in the tropical region and southern hemisphere. The long-term, zonally-averaged precipitation change to temperature change resembles the inter-annual version of the same ratio, except in the tropics over land. Ideas are presented on the reasons for the similarities and differences between the precipitation-temperature relations on the two time scales. Calculations of the ratio of linear precipitation increase to temperature increase over the period are calculated for both the tropics and the globe, and ocean and land. The global number is calculated to be about 2% precipitation change per degree temperature increase. Recorded presentation
Session 12, Detection and attribution of climate change: Part I
Wednesday, 23 January 2008, 4:00 PM-5:30 PM, 215-216
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